Rotational control structure of pneumatic tool

ABSTRACT

A rotational control structure of a pneumatic tool includes a housing provided with a cylinder unit. The cylinder unit has a bottom wall with two through holes and a guide post extending outwardly. The guide post has a gas passage and a gas outlet. The guide post is closely connected with a rotatable control ring leaning against the bottom wall. A sealing ring is provided between the bottom wall and the guide post. The control ring has a control passage therein. The control ring is rotatable for the control passage to communicate with one of the through holes of the bottom wall, thereby controlling the forward/reverse rotation of the pneumatic tool.

FIELD OF THE INVENTION

The present invention relates to a pneumatic tool, and more particularly to a pneumatic tool having a structure that controls the forward and reverse rotation of the pneumatic tool.

BACKGROUND OF THE INVENTION

As shown in FIG. 7 and FIG. 8, a conventional pneumatic tool has a cylinder unit 6 driven by a high-pressure gas to rotate in a forward or reverse direction. The forward or reverse rotation of the cylinder unit 6 is switched by an operable control member 7. In the above conventional device, the cylinder unit 6 and the control member 7 are accommodated in a housing 8. The cylinder unit 6 has a main body 61 and a rear cover 62. The rear cover 62 is provided with two gas passages 63, 64. The gas enters one of the two gas passages 63, 64 to rotate the cylinder unit 6 in the forward or reverse direction. The control member 7 has a control passage 71 therein for communicating with an external high-pressure gas. The control member 7 can be operated to rotate for the control passage 71 to communicate with one of the gas passages 63, 64 of the cylinder unit 6, so that the high-pressure gas is guided into the cylinder unit 6 to generate the corresponding rotation.

The control member 7 leans against the rear cover 62, enabling the control passage 71 to communicate with the gas passages 63, 64. Because gas leakage may affect the driving efficiency, the end surfaces of the two must be very flat so as to be in close contact with each other. However, it will cause technical and cost problems for extremely high machining precision.

Moreover, this conventional structure encounters a dilemma in assembly, that is, the control member 7 must be in close contact with the rear cover 61 to avoid gas leakage, but if the two are too tight, it will cause the problem that it is difficult to operate the control member 7. The width of the main body 61 of the cylinder unit 6 is slightly greater than that of the rear cover 62. The inner wall of the housing 8 is formed with a stepped edge 81. The main body 61 is mounted below the stepped edge 81. The rear cover 62 is mounted above the stepped edge 81. While the rear cover 62 abuts against the control member 7, the main body 61 is blocked by the stepped edge 81, thereby allowing the control member 7 to rotate smoothly. However, based on the design limitation of the overall size of the pneumatic tool, the stepped edge 81 is limited to have a small thickness, resulting in a low structural strength, which is liable to be crushed and collapsed, resulting in damage to the pneumatic tool.

SUMMARY OF THE INVENTION

The present invention is to provide a rotational control structure of a pneumatic tool, which improves the arrangement of the components of the rotational control structure, so that the components won't be damaged when they are in close contact with each other, and the operation can be performed smoothly.

In order to achieve the aforesaid object, a rotational control structure of a pneumatic tool is provided. The pneumatic tool comprises an intake seat for communicating with an external high-pressure gas. The intake seat is connected with a cylinder unit. The cylinder unit is connected with a tool head. The cylinder unit has a rear cover. The rear cover has a first through hole and a second through hole. The first through hole allows the gas to enter the cylinder unit for driving the tool head to rotate in a forward direction. The second through hole allows the gas to enter the cylinder unit for driving the tool head to rotate in a reverse direction opposite to the forward direction. The rotational control structure comprises a housing and a control ring.

The housing is configured to accommodate the cylinder unit. The housing has a bottom wall leaning against the rear cover. The bottom wall has a third through hole communicating with the first through hole and a fourth through hole communicating with the second through hole. An outer periphery of the bottom wall is formed with a first annular groove. A first sealing ring is embedded in the first annular groove. The bottom wall is provided with a guide post extending outwardly from the housing. A gas passage is defined in the guide post and communicates with the intake seat. A gas outlet is provided on a side of the guide post. A second annular groove and a third annular groove are disposed at two sides of the gas outlet of the guide post, respectively. A second sealing ring and a third sealing ring are embedded in the second annular groove and the third annular groove, respectively.

The control ring is rotatably fitted on the guide post. The control ring has an axial end surface and a radial inner annular surface. The end surface leans against the bottom wall. The end surface is provided with an annular wall surrounding the first annular groove and pressing the first sealing ring. The inner annular surface is in close contact with the guide post to surround the second annular groove and the third annular groove and press the second sealing ring and the third sealing ring. A control passage is defined in the control ring. A control inlet is formed on the inner annular surface. A control outlet is formed on the end surface. The control ring is rotatable between a first position and a second position. When the control ring is rotated to the first position, the control outlet communicates with the third through hole. When the control ring is rotated to the second position, the control outlet communicates with the fourth through hole. The control ring is within the above rotation range, and the control inlet is always in communication with the gas outlet.

In an embodiment, a spacer is disposed between the control ring and the intake seat. The spacer is pressed by a plurality of springs disposed on the intake seat to lean against the control ring, so that the end surface of the control ring leans against the bottom wall through the force of the springs.

In an embodiment, the housing is provided with an outer casing. A bottom end of the outer casing leans against the annular wall of the control ring. The bottom end of the outer casing is provided with a limiting recess. The annular wall is provided with a limiting block inserted into the limiting recess. The limiting block leans against either end of the limiting recess when the control ring is rotated to the first position or the second position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the present invention;

FIG. 2 is an exploded view of the present invention;

FIG. 3 is a cross-sectional view of the present invention;

FIG. 4 and FIG. 5 are schematic views of the present invention when in use, showing that the forward and reverse rotation is switched by the control ring;

FIG. 6 is a schematic view of the present invention when in use, showing that the control ring is used to adjust the gas intake amount;

FIG. 7 is an exploded view of a conventional pneumatic tool; and

FIG. 8 is a cross-sectional view of the conventional pneumatic tool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

Referring to FIGS. 1 to 3, the present invention discloses a rotational control structure of a pneumatic tool. The pneumatic tool mainly comprises an intake seat 11 for communicating with an external high-pressure gas, a cylinder unit 12, and a tool head 13. The three are sequentially connected to guide the high-pressure gas into the cylinder unit 12, thereby driving the tool head 13 to rotate. The cylinder unit 12 has a rear cover 121. The rear cover 121 has a first through hole 122 and a second through hole 123 to communicate with the cylinder unit 12 in different paths, so that the gas can enter the cylinder unit 12 to drive the cylinder unit 12 to rotate in different directions, thereby driving the tool head 13 to rotate in a corresponding direction. The first through hole 122 allows the gas to drive the tool head 13 to rotate in a forward direction. The second through hole 123 allows the gas to drive the tool head 13 to rotate in a reverse direction opposite to the forward direction.

The cylinder unit 12 is accommodated in a housing 2 having a bottom wall 21. The rear cover 121 leans against the bottom wall 21. The bottom wall 21 has a third through hole 211 communicating with the first through hole 122 and a fourth through hole 212 communicating with the second through hole 123. A guide post 22 extending outwardly from the housing 2 is disposed at the center of the bottom wall 21. A gas passage 23 is defined in the guide post 22 and communicates with the intake seat 11. A gas outlet 24 is provided on the side of the guide post 22. The high-pressure gas is guided into the gas passage 23 and discharged via the gas outlet 24.

The guide post 22 is sleeved with a rotatable control ring 3. The control ring 3 has an axial end surface 31 and a radial inner annular surface 32. The end surface 31 leans against the bottom wall 21. The inner annular surface 32 is in close contact with the guide post 22. A control passage 33 is defined in the control ring 3. A control inlet 34 is formed on the inner annular surface 32. A control outlet 35 is formed on the end surface 31. When the control ring 3 is rotated, the positions of the control inlet 34 and the control outlet 35 are changed accordingly. After the control ring 3 is sleeved on the guide post 22, the intake seat 11 is fixedly connected to the guide post 22 so that and the control ring 3 is confined and positioned by the intake seat 11.

The control ring 3 must lean against the bottom wall 21 surely, but it must not be too tight to rotate the control ring 3. Therefore, in the embodiment, a spacer 4 is disposed between the control ring 3 and the intake seat 11. The intake inlet 11 is provided with a plurality of receiving holes 111. A spring 41 is disposed in each of the receiving holes 111. The spacer 4 is pressed by each spring 41 to lean against the control ring 3, so that the end surface 31 of the control ring 3 is pressed against the bottom wall 21 by the force of the spring 41. Accordingly, the force of the control ring 3 against the bottom wall 21 can be adjusted by the spring 41, not being too tight.

In addition, the outer periphery of the bottom wall 21 is formed with a first annular groove 25. A first sealing ring 51 is embedded in the first annular groove 25. The end surface 31 of the control ring 3 is provided with an annular wall 36 surrounding the first annular groove 25 and pressing the first sealing ring 51. A second annular groove 26 and a third annular groove 27 are disposed at two sides of the gas outlet 24 of the guide post 22, respectively. A second sealing ring 52 and a third sealing ring 53 are embedded in the second annular groove 26 and the third annular groove 27, respectively. The inner annular surface 32 of the control ring 3 surrounds the second annular groove 26 and the third annular groove 27 and presses the second sealing ring 52 and the third sealing ring 53. By the respective sealing rings 51, 52, and 53, it is possible to prevent the gas from leaking at the place where they are placed to affect the driving efficiency.

With the above structure, the control ring 3 can be operated to rotate between a first position and a second position relative to the guide post 22, thereby controlling the tool head 13 to be rotated in a forward or reverse direction. In detail, the gas outlet 24 of the guide post 22 has a sufficient width, such that the control inlet 34 of the control ring 3 is always in communication with the gas outlet 24 between the first position and the second position, allowing the gas to enter the control passage 33. When the control ring 3 is rotated to the first position as shown in FIG. 4, the control outlet 35 of the control ring 3 communicates with the third through hole 211 of the bottom wall, and the gas is guided into the third through hole 211 to enter the cylinder unit via the first through hole of the rear cover, thereby driving the tool head to rotate in the forward direction. On the other hand, when the control ring 3 is rotated to the second position as shown in FIG. 5, the control outlet 35 of the control ring 3 communicates with the fourth through hole 212 of the bottom wall, and the gas is guided into the fourth through hole 212 to enter the cylinder unit via the second through hole of the rear cover, thereby driving the tool head to rotate in the reverse direction.

In this embodiment, as shown in FIG. 2, the housing 2 is provided with an outer casing 14. The bottom end of the outer casing 14 leans against the annular wall 36 of the control ring 3. The bottom end of the outer casing 14 is provided with a limiting recess 15. The annular wall 36 is provided with a limiting block 37 inserted into the limiting recess 15. The limiting block 37 is moved in the limiting recess 15 with the rotation of the control ring 3. As shown in FIG. 4 and FIG. 5, when the control ring 3 is rotated to the first position or the second position, the limiting block 37 leans against either end of the limiting recess 15, thereby limiting the rotation of the control ring 3, without excessive operation.

The invention is characterized in that the first, second and third sealing rings 51, 52, 53 are configured to block the gap between the control ring 3 and the abutting component to enhance the function of preventing gas leakage. Accordingly, the control ring 3 can prevent gas leakage without being in close contact with the abutting component, thereby avoiding the mutual wear and damage between the components. Besides, the control ring 3 can be rotated smoothly to improve its operability.

In addition to the function of switching the forward and reverse rotation of the pneumatic tool, the control ring 3 has a function of adjusting the gas intake amount to control the driving gas pressure. In detail, as shown in FIG. 6, when the control ring 3 is rotated and the control outlet 35 does not completely overlap with the third through hole 211 or the fourth through hole 212 of the bottom wall, only a partial area overlapped, that is, the area of the gate is reduced, and the amount of gas entering the third through hole 211 or the fourth through hole 212 is reduced, and the gas pressure for driving the tool head is reduced.

Although particular embodiments of the present invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the present invention. Accordingly, the present invention is not to be limited except as by the appended claims. 

What is claimed is:
 1. A rotational control structure of a pneumatic tool, the pneumatic tool comprising an intake seat for communicating with an external high-pressure gas, the intake seat being connected with a cylinder unit, the cylinder unit being connected with a tool head, the cylinder unit having a rear cover, the rear cover having a first through hole and a second through hole, wherein the first through hole allows the gas to enter the cylinder unit for driving the tool head to rotate in a forward direction, and the second through hole allows the gas to enter the cylinder unit for driving the tool head to rotate in a reverse direction opposite to the forward direction; the rotational control structure comprising: a housing for accommodating the cylinder unit, the housing having a bottom wall leaning against the rear cover, the bottom wall having a third through hole communicating with the first through hole and a fourth through hole communicating with the second through hole; an outer periphery of the bottom wall being formed with a first annular groove, a first sealing ring being embedded in the first annular groove; the bottom wall being provided with a guide post extending outwardly from the housing, a gas passage being defined in the guide post and communicating with the intake seat, a gas outlet being provided on a side of the guide post; a second annular groove and a third annular groove being disposed at two sides of the gas outlet of the guide post respectively, a second sealing ring and a third sealing ring being embedded in the second annular groove and the third annular groove respectively; a control ring rotatably fitted on the guide post; the control ring having an axial end surface and a radial inner annular surface, wherein the control ring is pressed by a plurality of springs disposed on the intake seat such that the end surface leans against the bottom wall through a force of the springs; the end surface being provided with an annular wall surrounding the first annular groove and pressing the first sealing ring, the inner annular surface being in close contact with the guide post to surround the second annular groove and the third annular groove and press the second sealing ring and the third sealing ring; a control passage being defined in the control ring, a control inlet being formed on the inner annular surface, a control outlet being formed on the end surface; the control ring being rotatable in a rotation range between a first position and a second position where the control inlet is always in communication with the gas outlet, wherein when the control ring is rotated to the first position, the control outlet communicates with the third through hole; when the control ring is rotated to the second position, the control outlet communicates with the fourth through hole.
 2. The rotational control structure of the pneumatic tool as claimed in claim 1, wherein a spacer is disposed between the control ring and the intake seat, and the spacer is pressed by the springs to lean against the control ring.
 3. The rotational control structure of the pneumatic tool as claimed in claim 1, wherein the housing is provided with an outer casing, a bottom end of the outer casing leans against the annular wall of the control ring; the bottom end of the outer casing is provided with a limiting recess, the annular wall is provided with a limiting block inserted into the limiting recess, and the limiting block leans against either end of the limiting recess when the control ring is rotated to the first position or the second position. 